IEnumerable vs IQueryable , which one to use in SOA and non-SOA?

Question

I am writing a Service Layer which has classes with methods returning lists of business objects, what should those methods' return types be ? IEnumerable or IQueryable and Why ?

Thanks

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Fahad

Answer 1

On 3/2/2012 3:47 PM, Fahad349 wrote:

> I am writing a Service Layer which has classes with methods returning

> lists of business objects, what should those methods' return types be ?

> IEnumerable or IQueryable and Why ?

>

 

It should return a List<T> which can be queried and enumerated.

 

 

Answer 2

Hi Fahad349,

Welcome to MSDN Forum.

The primary difference is that the extension methods defined for IQueryable<T> take Expression objects instead of Func objects, meaning the delegate it receives is an expression tree instead of a method to invoke. IEnumerable<T> is great for working with in-memory collections, but IQueryable<T> allows for a remote data source, like a database or web service.

Here's an article I think can help you.

http://odetocode.com/Articles/738.aspx

Best Regards

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Allen Li [MSFT]
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